Fix false-positive in expr_or_init and in the invalid_from_utf8 lint
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| // false-positive, so until we can reliably avoid those false | ||
| // postive we don't lint on them. Example of FP below. |
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Obviously, this is out of scope for this PR, but I'm curious why this PR is implemented as a HIR analysis instead of a MIR analysis? We have a dataflow framework for MIR that can answer these kinds of questions ("do we definitely know the value of this variable at this point in the program?") and it seems like it would be much simpler to write this as a MIR pass.
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The expr_or_init method came from clippy, same for invalid_from_utf8 which also came from clippy and both of them were using the HIR, so there is a bit a historical precedent.
As for implementing the lint as a MIR lint, it could probably be done, but I also remember MIR lints being more tricky to do, in part because MIR is much less like surface Rust than MIR is but also because the cargo check/build difference of MIR lints makes MIR lints less attractive; I don't know if it would apply here. I will have to check it.
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…ywiser
Fix false-positive in `expr_or_init` and in the `invalid_from_utf8` lint
This PR fixes the logic for finding initializer in the `expr_or_init` and `expr_or_init_with_outside_body` functions.
If the binding were to be mutable (`let mut`), the logic wouldn't consider that the initializer expression could have been modified and would return the init expression even-trough multiple subsequent assignments could have been done.
Example:
```rust
let mut a = [99, 108, 130, 105, 112, 112]; // invalid, not UTF-8
loop {
a = *b"clippy"; // valid
break;
}
std::str::from_utf8_mut(&mut a); // currently warns, with this PR it doesn't
```
This PR modifies the logic to excludes mutable let bindings.
Found when using `expr_or_init` in rust-lang#119220.
r? compiler
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…ywiser
Fix false-positive in `expr_or_init` and in the `invalid_from_utf8` lint
This PR fixes the logic for finding initializer in the `expr_or_init` and `expr_or_init_with_outside_body` functions.
If the binding were to be mutable (`let mut`), the logic wouldn't consider that the initializer expression could have been modified and would return the init expression even-trough multiple subsequent assignments could have been done.
Example:
```rust
let mut a = [99, 108, 130, 105, 112, 112]; // invalid, not UTF-8
loop {
a = *b"clippy"; // valid
break;
}
std::str::from_utf8_mut(&mut a); // currently warns, with this PR it doesn't
```
This PR modifies the logic to excludes mutable let bindings.
Found when using `expr_or_init` in rust-lang#119220.
r? compiler
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Rollup of 25 pull requests Successful merges: - rust-lang#134076 (Stabilize `std::io::ErrorKind::InvalidFilename`) - rust-lang#136842 (Add libstd support for Trusty targets) - rust-lang#137314 (change definitely unproductive cycles to error) - rust-lang#137504 (Move methods from Map to TyCtxt, part 4.) - rust-lang#137621 (Add std support to cygwin target) - rust-lang#137701 (Convert `ShardedHashMap` to use `hashbrown::HashTable`) - rust-lang#138109 (make precise capturing args in rustdoc Json typed) - rust-lang#138161 (Add PeekMut::refresh) - rust-lang#138162 (Update the standard library to Rust 2024) - rust-lang#138174 (Elaborate trait assumption in `receiver_is_dispatchable`) - rust-lang#138175 (Support rmeta inputs for --crate-type=bin --emit=obj) - rust-lang#138269 (uefi: fs: Implement FileType, FilePermissions and FileAttr) - rust-lang#138313 (Update books) - rust-lang#138318 (Rustdoc: remove a bunch of `@ts-expect-error` from main.js) - rust-lang#138331 (Use `RUSTC_LINT_FLAGS` more) - rust-lang#138333 (Rebuild llvm spuriously less frequently) - rust-lang#138343 (Enable `f16` tests for `powf`) - rust-lang#138345 (Some autodiff cleanups) - rust-lang#138346 (naked functions: on windows emit `.endef` without the symbol name) - rust-lang#138347 (Reduce `kw::Empty` usage, part 2) - rust-lang#138360 (Fix false-positive in `expr_or_init` and in the `invalid_from_utf8` lint) - rust-lang#138371 (Update compiletest's `has_asm_support` to match rustc) - rust-lang#138372 (Refactor `pick2_mut` & `pick3_mut` to use `get_disjoint_mut`) - rust-lang#138376 (Item-related cleanups) - rust-lang#138377 (Remove unnecessary lifetime from `PatInfo`.) r? `@ghost` `@rustbot` modify labels: rollup
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…iaskrgr Rollup of 8 pull requests Successful merges: - rust-lang#138161 (Add PeekMut::refresh) - rust-lang#138174 (Elaborate trait assumption in `receiver_is_dispatchable`) - rust-lang#138313 (Update books) - rust-lang#138347 (Reduce `kw::Empty` usage, part 2) - rust-lang#138360 (Fix false-positive in `expr_or_init` and in the `invalid_from_utf8` lint) - rust-lang#138372 (Refactor `pick2_mut` & `pick3_mut` to use `get_disjoint_mut`) - rust-lang#138376 (Item-related cleanups) - rust-lang#138377 (Remove unnecessary lifetime from `PatInfo`.) r? `@ghost` `@rustbot` modify labels: rollup
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…iaskrgr Rollup of 8 pull requests Successful merges: - rust-lang#138161 (Add PeekMut::refresh) - rust-lang#138174 (Elaborate trait assumption in `receiver_is_dispatchable`) - rust-lang#138313 (Update books) - rust-lang#138347 (Reduce `kw::Empty` usage, part 2) - rust-lang#138360 (Fix false-positive in `expr_or_init` and in the `invalid_from_utf8` lint) - rust-lang#138372 (Refactor `pick2_mut` & `pick3_mut` to use `get_disjoint_mut`) - rust-lang#138376 (Item-related cleanups) - rust-lang#138377 (Remove unnecessary lifetime from `PatInfo`.) r? `@ghost` `@rustbot` modify labels: rollup
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Rollup merge of rust-lang#138360 - Urgau:fix-fp-expr_or_init, r=wesleywiser Fix false-positive in `expr_or_init` and in the `invalid_from_utf8` lint This PR fixes the logic for finding initializer in the `expr_or_init` and `expr_or_init_with_outside_body` functions. If the binding were to be mutable (`let mut`), the logic wouldn't consider that the initializer expression could have been modified and would return the init expression even-trough multiple subsequent assignments could have been done. Example: ```rust let mut a = [99, 108, 130, 105, 112, 112]; // invalid, not UTF-8 loop { a = *b"clippy"; // valid break; } std::str::from_utf8_mut(&mut a); // currently warns, with this PR it doesn't ``` This PR modifies the logic to excludes mutable let bindings. Found when using `expr_or_init` in rust-lang#119220. r? compiler
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This PR fixes the logic for finding initializer in the
expr_or_initandexpr_or_init_with_outside_bodyfunctions.If the binding were to be mutable (
let mut), the logic wouldn't consider that the initializer expression could have been modified and would return the init expression even-trough multiple subsequent assignments could have been done.Example:
This PR modifies the logic to excludes mutable let bindings.
Found when using
expr_or_initin #119220.r? compiler